1. Field of the Invention
The invention relates to an image processing system which may be utilized to recognize and measure parts, while using various illumination techniques for its optical pick-up stage.
2. Description of the Prior Art
Image processing systems that are referred to as BVS produce information about a given subject, then supply that information to a computer for processing. For best results, an image processing system should first obtain critical information about the image to be processed. For increased processing speed with simultaneous reduction of the outlay, it is advantageous to reduce the quantity of data as early as possible with respect to the desired information (see the periodical "industrie-elektrik+electronic", Vol. 29, 1984, No. 9, pages 60 through 62). To achieve this data reduction as early as pick-up of the image, it is known (from the periodical "Elektronik", 4/19 Feb. 1988, pages 121 through 126), to employ active infrared light sources that are arranged to irradiate the subject to be measured. To achieve an adequately high signal-to-noise spacing between the background radiation and the infrared source, diodes with pulsed power sources and emission in the infrared wavelength range are used.
Image processing systems are increasingly used for recognizing and measuring parts. The precise matching of the subject illumination to the objective is essential for maintaining accuracy. Common difficulties are, in particular, reflections, an inadequate subject illumination caused by different luminescent intensities over the surface, as well as the ruggedness and weight of the illumination means.
In conventional optical pick-up stages for image processing systems, normal incandescent lamps, halogen lamps, and fluorescent tubes are commonly used for the illumination of the subjects. The light of these illumination sources shines directly onto the subject or it is directed onto the subject by mirrors or beam splitters. Indirect illumination of the subject by diffused light is also well-known. The disadvantages of these illumination devices are their great sensitivity and the requirement that they be synchronized with the video signal of the image-to-signal transducer and the camera, since they operate on alternating currents. In these known illumination devices, a diaphragm controls the brightness.